1. Field of the Invention
The present invention relates in general to wheelchair assemblies employed to provide transportation for invalids or the aged, and more specifically relates to such assemblies that are adapted to fulfill a special need the user may have.
2. Description of the Prior Art
The present invention is an improved wheelchair that is directly derived from normal, common day wheelchairs presently being used. Wheelchairs are used by a surprisingly large percentage of the people living in the world. They are used not only by the physically handicapped, but also by invalids that, either for reasons of age or other problems, no longer have the capability for walking or at least for walking any great distances.
The common wheelchair is formed from a frame supported by a large pair of main wheels and a smaller pair of steering caster wheels normally located forwardly of the drive wheels. A seat is fixed with respect to the frame so that a user is provided support while being transported about in the chair. However, such chairs are relatively uncomfortable for long usage, especially for the aged.
Other different wheelchair designs are known in the prior art ror providing various specific functions. For example, in U.S. Pat. No. 3,953,054 a six-wheeled chair is disclosed. The chair is supposed to be more maneuverable and has a seat that can be varied in height and inclination. Also, the patent indicates in an oblique fashion that there is some type of spring suspension associated with the seat that permits the seat "to rotate against the spring action around a horizontal axis between the hocks and a vertical projection of the crutch of the occupant." The chair is designed to be supported by only four of its six wheels at a time and the occupant of the chair can control which wheels will be supporting by leaning back in the seat or leaning forward. Apparently, the spring suspension referred to above is used to facilitate the operator's support wheel control.
Although the "054" patent, as previously pointed out, refers to a spring suspension in use with a seat, the patent in no way shows or describes any structure forming the spring suspension. Obviously, the patent is not designed to provide a wheelchair with a rocking seat. If the occupant attempted to rock in the chair, the chair would alternate from being supported by the rear four wheels to the front four wheels in a somewhat jarring fashion that would not only be uncomfortable but would require a relatively large amount of body action that would be tiring.
Another example of an unusual wheelchair construction is shown in U.S. Pat. No. 4,310,167. Such patent discloses a wheelchair with an articulated chassis that permits an operator to change the center of gravity of the chair to vary its stability according to conditions encountered by the operator. Also, the chair includes a shock absorber and spring means that positively maintain a subframe and seat frame assemblies of the chair in a predetermined relationship but permits the subframe and seat frame assemblies to articulate relative to one another for increasing comfort when traversing rough ground.
It is clear from the disclosure of the "167" patent that it is neither adapted to nor does it show or describe the use of a wheelchair having a rockable seat. Thus, the prior art has not been directed toward the development of a wheelchair with a rockable seat. In U.S. Pat. No. 3,100,638 a baby rocker that has a rockable seat is shown and described. The baby rocker is designed to permit a baby to rock as much as it pleases and to provide a rotating motion of the wheels of the rocker while the seat is rocked to enhance the attraction of the device for the baby. Although the device disclosed in "638" has a rockable seat, the patent is obviously directed to a totally different field of art than the wheelchair art and in no way would lead one skilled in the art to the present invention. This statement is supported by the fact that the "638" patent was issued in 1963 and yet over twenty-two years later, there are still no wheelchairs available having rockable seats.
The present invention is adapted to provide an improved wheelchair having a rockable seat that permits a user to enjoy the rocking motion of the seat similar to that provided by a normal rocking chair while the frame and wheels of the wheelchair are held in a completely stationary position.